End mill



. Sept. a

c. a. GAs'E: 2,129,417

END MILL Filed March 14', 1956 awgi , 1N OR Car] 69 Patented Sept. 6, 1938 UNITED sTA s END IVIILL Carl G. Gase, Parma, Ohio, assignor to Weldon Tool Company, Cleveland, Ohio, a corporation of Ohio Application March 14,

4 Claims.

My invention relates to end mills and other cutting tools.

An object of my invention is to provide an end mill having greater strength and supporting action for its cutting edges.

Another object is to provide an end mill having relatively short cutting edges and a relatively large face between the cutting edges.

Another object is to provide an end mill having cutting edges substantially confined to the end of the fillet.

Another object is to provide an end mill having a central depressed portion in the body of the end mill at'the cutting end so as to provide clearance between the said body and the mass to be cut.

Another object is to provide a depressed portion in the cutting end of an end mill, which depressed portion has sloping sides extending in a gradual and positive slope from the axial center of the end mill to the cutting edges.

A still further object is to provide an end mill having an arcuate depressed portion at its cutting end, the sloping sides of which arcuate depressed portion act as a brace for the cutting edges of the end mill.

A still further object is to provide an arcuate depressed portion in the cutting end of an end mill, the sloping sides of which arcuate portion act as a brace for the peripheral portion of the end mill at the cutting end.

Other objects and a fuller understanding may be had by referring to the accompanying drawing, taken in conjunction with the following description and claims, in which:

Figure 1 represents a side view of my end mill;

Figure 2 represents a view of my end mill with portions of the cutting end cut away to give a fragmentary view of the cutting end;

Figure 3 represents a left-hand end view looking at the cutting end of the end mill in Figure 1;

Referring to 'Figure 1, I show an end mill l5 having a flat, surface I6 on its engagingend for securing engagement of the end mill I5 to a shop machine. The end mill It: 'has a plurality of spiral flutes formed therein, leaving the fillets l8 in raised position extending longitudinally of the end mill l5 between the flutes As shown in the illustration, the fillets |8 are integral with the end mill and are extended in a spiral manner along the end mill.. The body portion or core I9 is shown in dotted lines' and represents the body of the end mill |5 within the fillets l8. Each fillet l8 has a narrow side 25 and a wider side 26 which converge to form a longitudinal edge 1936, Serial No. 68,897

28 extending along each of said fillets. Upon the cutting end of each fillet is a cutting edge 20 extending toward the axial center of the end mill.

Extending centrally of the cutting end of the end mill I5, between the cutting edges 20, is an arcuate depressed portion 22. The cutting edges 20 are substantially confinedto ends of the fillets 8 and the arcuate depressed portion 22 extends across the end of the body portion l9. The cut ting clearances 2| extend in a slightly sloping manner from the cutting edges 20. There is a recess 24 cut into the end of the body portion l9 at the terminus of each of the fillets IB. These recesses 24 extend inwardly and are somewhat sloping. The flute clearance 23 extends from each cutting clearance 2| back to each recess 24 and slopes from the cutting clearance down to the niche or recess 24 and also slopes slightly outwardly so as to converge into the flute.

In Figure 2, the arrangement of the parts upon the cutting end is well shown by cutting away a portion of the cutting end. The dead center hole 21 in the axial center of the end mill is the conventional hole used in making the tool. The arcuate depressed portion is shown extending substantially across the end of the end mill l5 and between the cutting edges 20. The fillet upon the rear side of the end mill is shown as extending out beyond the arcuate depressed portion, and the narrower side 25 of the fillet I8, is shown as pointing down. The longitudinal edges 28 are shown as terminating at the cutting edge.

Figure 3 being a view looking at the left end of the end mill of Figure 1, shows in detail the arrangement of the respective parts upon the cutting end of the end mill. The arcuate depressed portion 22 is shown as extending across substantially the end of the body of the end mill, having the dead center hole-21 in the axial center thereof. As the cutting edges 20 are slightly undercut, only the wider side 26 of each fillet is shown spirally up the end mill. The cutting clearance 2| upon each end of the fillet is shown as defining a cutting edge 20 upon one side of the cutting clearance 2|. Cut down into the end mill is .the recess or inward cut 24 at the end of each fiute |'I, so that 'the depression of each flute I1 is carried inwardly of the' end mill toward the axial center thereof. The recess 24 acts as a. limit which aids in defining the extent of the flute clearance 23 so that in grinding the flute clearance 23, the grinder need not be brought too close to the cutting edges 20. The flute clearance 23 edges ona lateral end face of said mill comprisis shown as extending between each of the recesses 24 and the cutting clearances 2|. The surface of the flute clearances is sloped at a slight incline from the cutting clearances 2| down to the recess 24 and also slopes slightly back to converge with the wider side 26 of each fillet [8.

It is seen by referring to Figures 1, 2, and 3, that the arcuate depressed portion 22 by its arcuate nature has walls which act as a substantial brace and support for the cutting edges 20 on the end of each fillet. It is also seen that such a structure permit the confining of the cutting edges 20 to the cutting end of the fillet without substantially extending inwardly upon the body of the end mill. The absence of this supporting structure would necessitate having much wider cutting edges and extending inwardly in order to give suflicient strength to the cutting edges. It is seen that the stress against the cutting edges 20 is met not only by the bracing action of the fillet back. of each cutting edge, but also by the bracing action of the wall of the arcuate depressed portion 22.

Since the end mill is moved laterally as well as rotatively, it is necessary to have a clearance between the center or body of the end mill and the mass to be cut. This limits the width of the cutting edges. The advantage of my end mill with the cutting edges upon the end of the fillets and a relatively wide depressed arcuate portion between them, having the sloping walls supporting and bracing these short cutting edges, is such that the short cutting edges are not prone to break off and chip because of lack of support. My structure in its bracing action gives maximum strength to the .short cutting edges and permits them to be substantially confined to the cutting end of the fillet.

Although I have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope" of the invention as hereinafter claimed. I claim as my invention:

1. An end mill having a plurality of cutting ing, in combination, a fluted member having a body portion and a plurality of fillets extending along the body portion, said fillets having longitudinal cutting edges extending thereon, a lateral cutting edge on the lateral end face of each of said fillets, each said lateral cutting edge being disposed substantially at right angles to the longitudinal axis of said mill and the outer end of each saidtlateral cutting edge meeting the longitudinal cutting edge of each said fillet to form a substantially-sharp cutting corner, the length of each of said lateral cutting edges being substantially limited to the depth of the flutes, said body portion having a depressed portion intermediate of the inner ends of the lateral cutting edges, said depressed portion being shallow adjacent the inner ends of the lateral cutting edges and having a gradual slope and being deeper inwardly towards the longitudinal axis of the end mill.

2. An end mill having a plurality of cutting edges on a lateral end face of said mill comprising, in combination, a fluted member having a body portion and a plurality of fillets extending along the body portion, said fillets having lon- I gltudinal cutting edges extending thereon, a lateral cutting edge on the lateral end face of each of said fillets, each said lateral cutting edge being disposed substantially at right angles to the longitudinal axis of said mill and the outer end of each of said lateral cutting edge meeting the longitudinal cutting edge of each said fillet to form a substantially sharp cutting corner, said fluted member having a gradually sloping depressed end portion extending across the end of said body portion intermediate of said lateral cutting edges and having boundary points located near the outer edge of the body portion, the inner ends of ,the lateral cutting edges being adjacent the outer boundary of the depressed end portion and extending outwardly toward the longitudinal cutting edges.

3. An end mill capable of cutting at a marked increase in speed as compared with other end mills in standard practice and at the same time maintaining cutting edges comparable with the cutting edges of said other end mills, said end mill comprising a fluted body member having a plurality of fillets with longitudinal cutting edges extending therealong, a lateral cutting edge on the lateral end face of each of -said fillets, each said lateral cutting edge being disposed substantially at right angles to the longitudinal axis of said mill and the outer end of each said lateral cutting edge meeting the longitudinal cutting edge of each said fillet to form a substantially sharp cutting corner, the cutting end of the said end mill being modified from standard practice by having a substantial decrease in the length of-the lateral cutting edges and by having a substantial increase in distance between the inner ends of the lateral cutting edges and by having a relatively wide and shallow depressed portion intermediate the inner ends of the lateral cutting edges, said depressed portion extending to the inner ends of the lateral cutting edges and deepening inwardly toward the longitudinal axis of the end mill.

4. An end mill capable of cutting at a marked increase-in speed as compared with other end mills in standard practice and at the same time I maintaining cutting edges comparable with the cutting edges of said other end mills, said end mill comprising a fluted body member having a plurality of fillets with longitudinal cutting edges extending therealong, a lateral cutting edge on the lateral end face of each of said fillets, each said lateral cutting edge being disposed substantially at right angles to the longitudinal axis of said mill and the outer end of each said lateral cutting edge meeting the longitudinal cutting edge of each said fillet to forma substantially sharp cutting corner, the cutting end of the said end mill being modified from standard practice by having a substantial decrease in the length of the lateral cutting edges and by having a substantial increase in distancebetween the inner ends of the lateral cutting edges and by having a relatively wide and shallow depressed portion intermediate the inner ends of the lateral cutting edges, said depressed portion being shallow adjacent the inner ends of the lateral cutting edges and having a gradual slope and being deeper inwardly towards the longitudinal axis of the end mill.

CARL G. GASE. 

